early 14c., busshel, measure of capacity containing four pecks or eight gallons, from Old French boissel "bushel" (13c., Modern French boisseau), probably from boisse, a grain measure based on Gallo-Roman *bostia "handful," from Gaulish *bosta "palm of the hand" (compare Irish bass, Breton boz "the hollow of the hand").
The exact measure varied from place to place and according to commodity, and though in 19c. in Britain it acquired a precise legal definition, it varied in U.S. from state to state. It has been used since late 14c. loosely to mean "a large quantity or number." Attested from late 14c. as "a bushel basket." To hide (one's) light under a bushel is from Matthew v.15.